Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:6.3.4.6 (urease)
 7,490 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Three laboratory-prepared urease reagents were compared with a commercial preparation supplied for routine use on the Beckman Blood Urea Nitrogen Analyzer. There were discrepancies in results for urea nitrogen among the four urease reagents when matching serum and the corresponding oxalate/fluoride treated plasma were compared as measured with the Beckman Analyzer and continuous-flow (AutoAnalyzer) method. All four urease preparations were affected by fluoride, but to different extents. We believe that an effective laboratory reagent can be prepared in the laboratory at significantly lower cost.
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PMID:Four commercial urease reagents and a laboratory-prepared reagent compared for analysis of blood urea nitrogen with the Beckman analyzer. 126 Oct 19

The composition of 3,084 urinary calculi was determined using an infrared spectrophotometer. Mixed calcium oxalate-calcium phosphate stones were most frequently implicated. Of the urinary calculi analyzed 199 were associated with urinary tract infection. Escherichia coli was most frequently isolated (43 strains) and urease-producing organisms, such as Proteus mirabilis, were cultured from 40 patients. The core culture of 20 staghorn calculi yielded 15 isolates from 14 stones. There were 13 identical species isolated from the urine and stone specimens of 13 patients (65%), including 7 strains of P. mirabilis. These results suggest that cultures of urine specimens of urolithiasis patients, especially those with staghorn calculi, may help to elucidate the bacteriology of the stones.
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PMID:Composition of urinary calculi related to urinary tract infection. 150 58

Nephrolithiasis is a heterogeneous disorder, with varying chemical composition and pathophysiologic background. Although kidney stones are generally composed of calcium oxalate or calcium phosphate, they may also consist of uric acid, magnesium-ammonium phosphate, or cystine. Stones develop from a wide variety of metabolic or environmental disturbances, including varying forms of hypercalciuria, hypocitraturia, undue urinary acidity, hyperuricosuria, hyperoxaluria, infection with urease-producing organisms, and cystinuria. The cause of stone formation may be ascertained in most patients using the reliable diagnostic protocols that are available for the identification of these disturbances. Effective medical treatments, capable of correcting underlying derangements, have been formulated. They include sodium cellulose phosphate, thiazide, and orthophosphate for hypercalciuric nephrolithiasis; potassium citrate for hypocitraturic calcium nephrolithiasis; acetohydroxamic acid for infection stones; and D-penicillamine and alpha-mercaptopropionylglycine for cystinuria. Using these treatments, new stone formation can now be prevented in most patients.
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PMID:Etiology and treatment of urolithiasis. 196 46

To compare the frequency of urine infection in calcium oxalate and calcium phosphate stone formers, we reviewed charts from patients whose last renal stone submitted for analysis was predominantly composed of calcium phosphate in 118 and of calcium oxalate in 223. Positive cultures were commoner, but not significantly, in the phosphate than the oxalate stone formers, both in men (17 vs. 7.6%) and women (22 vs. 15%). Bacteria frequently producing urease were found in only 4% of the phosphate group. Urine leucocytes were slightly more frequent in the oxalate group for men and significantly so for women. The results do not support the concept that calcium phosphate stones are mainly due to infection with urease-producing or other bacteria.
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PMID:Comparison of urinary tract infection in calcium oxalate and calcium phosphate stone formers. 220 21

The efficacy of a diet designed to facilitate dissolution of feline magnesium ammonium phosphate (struvite) uroliths was evaluated in 30 cases of urolithiasis, sterile struvite uroliths dissolved in a mean of 36 days after initiation of dietary treatment. In 5 cases of urolithiasis, struvite urocystoliths associated with urease-negative bacterial urinary tract infection dissolved in a mean of 23 days after initiation of dietary and antimicrobial treatment. In 3 cases of urolithiasis, struvite urocystoliths associated with urease-positive staphylococcal urinary tract infection dissolved in a mean of 79 days after initiation of dietary and antimicrobial treatment. Dissolution of uroliths in cats fed the treatment diet was associated with concomitant remission of dysuria, hematuria, and pyuria, and reduction in urine pH and struvite crystalluria. In one case, a urocystolith composed of 100% ammonium urate, and in another case, a urolith composed of 60% calcium phosphate, 20% calcium oxalate, and 20% magnesium ammonium phosphate did not dissolve.
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PMID:Medical dissolution of feline struvite urocystoliths. 232 73

Extensive cultures of stones and urine were performed in 215 patients who underwent an operation for upper urinary tract calculi. Microorganisms could be cultured from the stone in 1 of every 3 patients. Despite the extended culture technique urease-producing microorganisms could be cultured from the stone in only 48% of the patients with calculi that contained magnesium ammonium phosphate. This finding suggests that an infection with urease-producing microorganisms is not obligatory for the formation of this type of stone. Of the patients with calcium oxalate phosphate stones 32% had positive stone cultures, which distinguished them from patients with pure calcium oxalate stones, only 8% of whom had a positive stone culture (p less than 0.001).
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PMID:Bacteriology of upper urinary tract stones. 232 12

Struvite nephrolithiasis is caused by infection with bacteria that possess the enzyme urease, and convert urea to ammonia that raises urine pH and crystallizes with magnesium and trivalent phosphate ion. Of the 75 of our 1431 stone patients with struvite stones 52 were women. Struvite stones occurred almost exclusively in women; a minority of women and most men had mixed stones of struvite and calcium oxalate. Increased serum creatinine levels and reduced creatinine clearance were common in patients with struvite stones, not in those with mixed stones; both were rare in calcium stone disease. Men and women with mixed struvite, calcium oxalate stones were hypercalciuric, but women with struvite stones were not. Patients with mixed stones usually had initial symptoms of stone passage, and were less likely to need surgery, including nephrectomy, or to form contralateral stones. Patients with struvite stones usually presented with infection or no symptom, not passage. We conclude that struvite stones occur in two forms. The struvite stone is a disease of women, presumably occurring de novo from infection. The mixed stones occur in both sexes, presumably from secondary infection in hypercalciuric patients who begin with calcium-oxalate stone disease.
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PMID:Reduced glomerular filtration rate and hypercalciuria in primary struvite nephrolithiasis. 343 Sep 61

Kidney stones have an overall incidence of two to three percent in western countries. In many patients, the disease process is difficult to control and recurrence rates are high: 20 to 50 percent over the subsequent ten years. The pathogenesis and standard methods of treatment for the five major types of stones (i.e., calcium oxalate, struvite, calcium phosphate, uric acid, and cystine) are reviewed. Three new drugs are reviewed in the context of their roles in the selective treatment of kidney stones. Cellulose sodium phosphate (Calcibind) is a nonabsorbable ion-exchange resin with a limited indication for the treatment of calcium stones associated with absorptive hypercalciuria Type I. Acetohydroxamic acid (Lithostat) is an urease-inhibitor that is indicated as adjunctive therapy in patients with chronic urea-splitting urinary tract infections and struvite stones. Potassium citrate (Urocit) is an investigational agent that has clinical efficacy in patients with calcium oxalate and calcium phosphate stones who are hypocitraturic. In addition, potassium citrate is an alkalinizing agent that can be used in patients with uric acid stones.
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PMID:New drug therapy for kidney stones: a review of cellulose sodium phosphate, acetohydroxamic acid, and potassium citrate. 389 14

The formation of some urinary tract stones (struvite stones) is known to be related to infection by urease-possessing microorganisms, such as Proteus sp. and some other bacteria. Ureaplasma urealyticum, a genital mycoplasma, contains also urease and is predominantly located in the urogenital tract. Its significance in the production of human urinary stones has not yet been elucidated. In this study, 135 human calculi obtained by surgery were analysed chemically and were cultured for the presence of conventional bacteria and U. urealyticum, 51 were ammonium magnesium phosphate stones and contained Proteus (27), E. coli (4), Staphylococcus epidermidis (3), Streptococcus D (2), Pseudomonas aeruginosa (1), Staphylococcus aureus (1), Corynebacterium (1), Candida albicans (1). U. urealyticum was isolated in one patient, from two different calculi (left and right) taken after an interval of fifteen days. Different bacteria were isolated from other calculi (oxalate, uric acid). This findings suggest that Ureaplasma urealyticum should be looked for in struvite calculi.
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PMID:[Comparative bacteriological and chemical analysis of kidney calculi. Apropos of 135 cases]. 653 Oct 61

Phosphate stones are divided in two groups: I. Infection stones = triple phosphate stones (struvite and carbonate apatite). II. Calcium phosphate stones = Hydroxy apatite. Ad I. For the formation of this stone, infection with urease-producing bacteria is essential. It is important to look for factors that cause infection and for metabolic abnormalities. Three possibilities for treatment are discussed: Acidifying the urine: orally with NH4NO3 or NH4Cl; dosage is possible up to 12 g a day (metabolic acidosis!). Irrigation for instance with Renacidin ; when using a nephrostomy-tube, one can start 5 days after the operation. It is important to look for fever and flank pain. Especially useful in cases with small residual stones. Reduction of phosphate excretion in urine ( Shorr -regimen). Some aluminium combinations reduce the intestinal phosphate absorption as a result of the formation of a nonabsorbable aluminium-phosphate combination. This can be combined with a low calcium- and phosphate diet. In several publications good results are shown. Also when using a less rigid regimen, satisfactory results are seen: decrease of the phosphate excretion from 30 to 17 mmol/24 h (own investigation). Urease-inhibitors result in a lower urine-pH and a decrease of the ammonium-concentration. there are only a few publications with results, but AHA seems able to reduce the stone size in 24% of the patients. Ad II. This stone is concerning formation and treatment much like the calcium oxalate stone. In case of an alkaline urine one must look for primary hyperparathyroidism and renal tubular acidosis.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Conservative therapy of phosphate calculi]. 653 26


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